The court heard Sefton was due to return to New Zealand on Saturday.His matters are next due for mention on May 13.
Kane's father, Eastern region surf lifesaving and education manager Leigh Sefton, told the Bay of Plenty Times that after the container was discarded from the window of a car and it slid along the road and "some coleslaw splattered onto the open door of another car, and a couple of pieces of coleslaw accidently landed on a man and a four-year old girl."
"This incident had nothing to do with Kane's lifesaving activities nor Surf Lifesaving NZ, and this happened during his down time," he said.
Mr Sefton said his son had pleaded guilty to wilful damage, and two charges of assault were yet to be resolved. The matter was due back in court in three weeks' time, he said.
"Any suggestion that Kane deliberately threw the container at anyone is totally off mark, and completely false. "Kane has already paid a thousands times over for his silly mistake," he said.
Kane is a Year 13 student at Tauranga Boys' College.
Principal Robert Mangan said he been unaware of the incident until the newspaper approached him for comment.
"It is disappointing to hear about this incident. Kane is a reasonably well-behaved young man at school and this silly action has had unfortunate consequences for him.
"I am pleased that he has taken responsibility for what he has done. Like I tell all my students, having a bit of forethought about your actions is important because if you don't it can end badly."
Mr Mangan said the college had recognised Kane's life-saving achievements, and most rising young athletes needed to appreciate they can become public property, and their actions "came under the microscope".
The 2016 Australian Surf Life Saving Championships were held on the Sunshine Coast from April 16-24.
Kane Sefton had won three national under 19 titles in March at Ohope Beach.
